Wafer temperature uniformity is important in atomic layer deposition (ALD) processes. Deposition uniformity in spatial ALD batch processes reactors can be challenging where the wafer is positioned on a susceptor moving above an infrared heating system. Traditionally, for improvement of temperature uniformity, multi-zone heating is used. However, the systems used for improved temperature uniformity are complex and the cost is proportional to the number of heating zones. Moreover, for spatial ALD systems with rotating susceptors it is very difficult to achieve good temperature distribution in the tangential direction and, as a result, leading and trailing edge temperatures are very difficult to homogenize with the rest of the wafer surface resulting in non-uniform deposition.
Therefore, there is a need in the art for apparatus and methods to increase deposition uniformity in batch processing chambers.